1. Field of the Invention
The present invention relates to a system for interfacing a Private Branch Exchange (PBX) with an Asynchronous Transfer Mode (ATM) network.
2. Description of the Related Art
In FIG. 1, a conventional system for interfacing a Private Branch Exchange (PBX) with an Asynchronous Transfer Mode (ATM) network is illustrated. In the prior art system, the PBX 20 is coupled to a plurality of subscriber extensions 11, 12, 13 and a central office switch 30 to provide communication service over a Public Switched Telephone Network (PSTN). Alternatively, the PBX 20 can be directly connected to the PSTN to provide communication service without any additional interface device. Moreover, the ATM network is coupled to a multimedia terminal 80 and a hub 60 via an ATM switch 40. The hub 60 of the ATM network 60 is coupled to a plurality of workstations 71, 72 to provide wide-band multimedia service.
In order for the PBX 20 to provide wide-band multimedia service through the ATM network, the PBX 20 must be connected to an ATM CES Interworking Function (ATM CES IWF) 50 to convert its signal frame into a corresponding ATM cell to be applied to the ATM switch 40. The conversion is necessary since the PBX communication process is completely different from the ATM network. The ATM CES IWF 50 serves as a proprietary interface to make a permanent virtual channel (PVC) connection between the PSTN and the ATM network to transmit the voice traffic of the PBX 20 by way of the PVC connection. Thus, in the conventional system, the ATM CEF IWF 50 must be separately provided to cross-interface between the PBX 20 and the ATM switch 40. However, the prior art system has drawbacks in that the ATM CEF IWF 50 is overloaded with the tasks of processing voice traffic calls due to the double signaling and the information exchanges occurring between two different networks. As a result, the prior art interfacing system is not efficient.
It is an object of the present invention to provide an apparatus for interfacing a PBX with an ATM network.
It is another object of the present invention to provide a method for interfacing a PBX with an ATM network.
According to the present invention, an apparatus for interfacing a PBX with an ATM network includes a circuit switch part for establishing an ATM communication channel to connect the ATM network if a subscriber requests an access to the ATM network, and an ATM network switch part for converting the signaling information from the ATM communication channel into the corresponding ATM network cell to be applied to the ATM network.
According to another aspect of the present invention, a method for interfacing a PBX with an ATM network includes the steps of establishing an ATM communication channel to connect the ATM network if a subscriber requests access to the ATM network, and converting the signaling information of the subscriber from the ATM communication channel into a corresponding ATM network cell to be applied to the ATM network.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more detailed description of preferred embodiments as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, the emphasis instead placed upon illustrating the principles of the invention.